This invention relates to solid or liquid-solid waste comminuting apparatus and particularly to a method and apparatus including means to readily replace bearing, seals, cutters and spacers due to wear on the comminuting apparatus.
The present technique of comminuting waste material into the nip of counter rotating cutters is disclosed in the prior art such as U.S. Pat. No. 4,630,781 to Brown, et al. Little attention however has been given to the replacement of bearings, seals, cutters, and spacers due to wear. The cutter edges tend to round thereby reducing the shear or scissor action and causing heat and lost production time during replacement. Bearings and seals eventually become contaminated by waste leading to eventual bearing failure. Since bearings and seals are confined to a cartridge, bearings failure usually occurs shortly after a seal failure.
It is impractical to operate a shredder with duel cutters which result in diminishing productivity. Duel cutters increase power demand, because of increased frictional resistance causing more frequent stalling and reversing of the rotors to clear the jam. The particle size will also gradually increase in size. Bearing and gear life will shorten due to increase loading of these components.
The present day shredders depending on the size of the apparatus now require one to five days to replace rotors. Occasionally cutters are sharpened in place to save lost production, but this remedy is not satisfactory. It may result in a cutter unable to be factory sharpened and require a new cutter.
It is important to replace all rotating wearing parts on a machine quickly without dismantling the machine. The present art requires removal of hoppers and separation of the machine frame and drive mechanism to obtain access to the bearings, seals and rotor shaft assembly with cutters and spacers.
The time required for servicing is an important cost factor since down time reduces production and time intensive work increases labor costs. Bearing-seal cartridges and new cutter-spacers can generally be installed on small machines in 4-8 hours since the rotor assemblies are relatively light and can be manually installed. Servicing the rotor assemblies of large machines generally require the use of cranes or mobile fork lift trucks and takes several days.
On occasion, shredders expected to process a variety of products. A selected style of cutter on a rotor shaft may be satisfactory for some of these products but not for all of them. The ability to change rotor configuration quickly, to satisfy all of these products will be a decided advantage.
Other references of interest include U.S. Pat. Nos. 4,630,781; 3,690,572 and 5,169,075. None of these patents however include the unique features of this invention.